Cut-out



May 1, 1928. 1,668,450

' J. M. FRIED CUT-OUT Filed .001. '27, 1922 2 Sheets-Shet 1 May 1, 192s. 1,668,450

J. M. FRIED CUT-OUT Filed Oct 27, 1922 2 Sheets-Sheet 2 Patented .May 1, 1928.

UNITED STATES JACOB E. FRIED, F VICKSB'URG, MISSISSIPPI.

' GUT-OUT.

Application filed hotelier 27, 1922. Serial No. 597,871. I

This invention relates to thermal safety cut-outs for electrical circuits and appliances and more particularly to the provision of novel means for preventing short-circuit ing or overfusing of such'cut -outs.

The invention contemplates as one of its important and novel features standardizing the size of the interfitting portions of the fuse block and plug of a cut-out for a given rated capacity so as to prevent the substitution of a plug having a higher rated capacity than that for which the cut-out is originally designed.

The invention further contemplates the provision of a fuse block provided with terminals designed to preventv the connection thereto of conductors of a larger size and capacity than that for which the block and associated plug are intended.

Other purposes and advantages of the invention, not specifically stated above, will suggest themselves from a complete understanding of the preferred embodiment disclosed by the following specification and accompanying drawings.

In the drawings, Figure 1 is a top plan view of a fuse block constructed in accordance with my invention.

' Figure 2 is a view in elevation of the lineside of the block.

Figure 3 is a view in elevation of the load-side of the block partly broken away to disclose the terminal connections for the load-conductors.

Figure 1 is a bottom plan View of the block partly broken away to disclose interior,constr'uction.

Figure 5 is a sectional View taken on the line 5-5 of Figure 1.

Figure 6 is a detailed sectional view showing the structure of one of the terminals at the line-side of the block.'

Figure 7 is a similar view showing the structure of one of theterminals at the loadside of the block, and y Figure 8 is a View of a fuse plug designed for use in connection with the aforementioned block. 4 Y

The fuse block 5 is composed of any suitable insulating material and is herein shown as provided with a pair of plug receiving sockets of the type indicated at 6 and 7 although it will be understood that any number of sockets of this type may be employed according to the "conditions of use.

The sockets 6 and 7 are provided with suitable liners in the form of threaded metal sleeves 8 and 9,fianged inwardly at their lower edges as indicated at 10 and 11 to rest squarely on the bottom of the said sockets. 'lhe flange 10 is held to the bottom of the socket 6 by nuts 12-12 and bolts lid--13 arranged as shown to advantage in Figure 5, the heads of the bolts 13 and 13 being disposed in recesses 14, formed in the bottom of the block. In like manner, the flange 11 is held to the bottom of the socket 7 by a duplicate arrange'nent of nuts l5.l5 and bolts 16 and 16, the heads of these bolts being disposed in recesses 17 corresponding to the aforementioned recesses let.

The bolts 13 and 16 are connected by strips 18 and 19 to suitable contact disks 20 and 21 mounted onthe block to one side of the said sockets as shown to advantage in Figure 1, these strips being disposed in suit able recesses and 23 formed in the bottom of the block and being confined at one end beneath the heads of the bolts 13 and 16 the remaining ends of the strips being fastened to or formed integral with the disks 20 and 21 as may be preferred. Each of the disks 20 and 21 is provided with a projecting and depending lip 24: fitting in a suitable notch formed in the block 5 so as to hold the disk in fixed relation therewith. Each of these disks is further provided with a binding screw 25 threadedly engaged therewith and a pair of upstanding lugs 26 disposed on opposite sides of the binding screw to assist in maintaining a conductor in confined rela: tion therebeneath.

The sockets 6 and 7 are cored out at the bottom to provide recesses 27 and 28 of a diameter considerably less than that of the said sockets. Positioned on the bottom of cumferential walls thereof, are suitable contacts 29 and 30 formed by upsetting the upper ends of a pair of conductor strips 31 and 32, these strips being extended downwardly through suitable openings 33-3 1, and thence horizontally through grooves 35 and 36 and connected at their opposite ends these recesses, in spaced relation to the cirto suitable conductor sockets or sleeves 37 and 38, these sleeves being mounted in the block 5 as shown to'advantage in Figures 4 and 7 and having their outer ends terminating flush with or in the plane of the load-side of the block and being each equipped with a set screw 39 by means of which the load conductors are secured therein. As shown to advantage in Figure 3, the heads of the screws 39 are disposed in recesses 40 provided in the body of the block 5;

In order to prevent accidental short-circuiting of any of the connections described in the foregoing, the aforementioned recesses and grooves are all filled with a suitable insulating compound 42 as shown to advantage in Figure 5.

v The fuse plug intended for use with the block described in the foregoing is shown to advantage in Figure 8 and comprises a relatively large body portion 43 having an external metal thread 44 for engaging the thread of the liner 8, said body being reduced below the portion 43 to provide a restricted insulating stem 45 carrying the contact tip 46 which, as is usual in such devices, is connected by the thermal wire 47 to the metal thread 44.

In accordance with my invention the size of the portion 45 of the plug will depend upon the rated capacity thereof, and will be received in the reduced portion or recess 27 of the socket 8 only in the event that the rated capacityof the plug does not exceed that for which the blockcarrying the said socket is originally designed. Asthe re- .cess of each socket is adapted to snugly receive the reduced portion of the plug originally intended to be used therewith, it

will be impossible to introduce a plug of a higher rated capacity as-the reduced portions of such plugs will be too large to enter the said recesses and establish proper connection between the arts.

As a-further or supp emental safeguard, the size of the load-conductor sockets is determined in accordance with the size of the recesses 27 and 28 and the size of the plug portions 45 intended to be received in said recesses so that it will be impossible to connect to the block conductors of a size or capacity greater than that for which the cut-out is orginally designed.

In the use of my invention, the line wires are fastened beneath the binding screws 25 and are held against displacement from beneathv the same, by means of the lugs 26.

The load-conductors are then inserted inthe ecaeeo through the strips 18 and 19 to the plugs and from the latter through the strips 31 and 32 to the sockets 37 and 38 and thence through the load-conductors (not shown).

Preferably, the length of the screws 39 is such that the same would be withdrawn from engagement with the load-conductors, if any attempt were made. to short-circuit the cut-out, by connecting wires beneath the heads of these screws and the heads of the screws 25. It will also be manifest that owing to the depth of the recesses 27 and 28 and the consequent disposal of the contacts 29 and 30 with respect to the liners 8 and 9, it will be extremely difficult to maintain a short-circuit wire in position between either the contact 29 and the liner 8 or the contact 30 and the liner 9. Having thus fully described what I now consider to be the preferred embodiment of my invention, I wish it understood that I do not limit myself to the exact construc- I tion and arrangement of parts herein set forth, but reservethe rlght to resort to such modifications as may later prove desirable,

wall of the socket, a secondcontact secured on and covering only the central bottom wall portion of the recess and spaced fromthe circumferential wall of the recess, a fuse plug presenting a body portion adapted to be received in said socket and a reduced stem portion depending from the lower end of the body and adapted to enter said recess, saidbody and stem portions of the plug being formed of insulating material,

.a contact tip secured to and covering only the central bottom portion of the stem and adapted to engage the contact in the recess, a contact sleeve surrounding the body portion of the plug adapted to engage the sleeve in said socket and a, fuse wire passing through a small opening in the stem of the plug and connected between the two conacts thereof. 7

-2. A thermal cut-out comprising a fuse block made of insulating material and provided with a socket having a centrally disposed and relatively deep recess leading downwardly therefrom, a contact sleeve lining the circumferential wall of the socket, a second contact secured on and covering only a relatively small central area of the res bottom wall of therecess and spaced from the circumferential wall of said recess, said secondco'ntact being hemispheficaliin shape and arranged with its curved surface facing sleeve surroundi the body portion of the upwardly, a fuse plug presenting a body plug and engagea 1e with the sleeve in said 10 portion adapted to be received in said socket socket and a fuse wire passing through a and a reduced stem of non-conducting matesmall opening in the stem of the plug and rial adapted to enter said recess, a contact connected between the two contacts thereof. tip secured to and covering only the central In testimony whereof I hereunto aflix my bottom portion. of the stem and adapted to signature.

engage the contact in the recess, a contact JACOB M. FRIED. 

